Two New Chromeno[3,2-c]Pyridine Derivatives from the Whole Plants of Thalictrum finetii and Their Antirotavirus Activity

Chemistry of Natural Compounds - Two new chromeno[3,2-c]pyridin derivatives, 8-acetyl-3-(hydroxymethyl)-7-methoxy-10H-chromeno[3,2-c]pyridin-10-one (1) and...     

Two New CPA-Type Indole Alkaloids from the Tobacco-Derived Fungus Aspergillus versicolor and the Anti-TMV Activity

Chemistry of Natural Compounds - Two new CPA-type indole alkaloids (1 and 2) were isolated from the fungus Aspergillus versicolor. Their structures were determined by means of HR-ESI-MS and...     

Design of a multi-cusp ion source for proton therapy

The permanent magnets of the discharge chamber in a multi-cusp proton source are studied and designed. The three electrode extraction system is adopted and simulated. A method to extract different amounts of current while keeping the beam emittance unchanged is proposed.     

Design of magnet and control of the beam emittance for Penning H- ion source

The design requirement and principle of the deflection magnet for Magnetron and Penning H- ion source are discussed.It is proved that there exists a maximum emittance for the beam that may be transformed by the magnet into a state with equal Twiss parameters of αr=αy and βr =βy,which is the requisite condition to get a minimum emittance at the entrance of RFQ after transporting by a LEBT with solenoids.For this maximum emittance,the corresponding magnetic field gradient index is 1.     

Aspergillines K and L,Two New Anti-TMV Indole Alkaloids from Fungus Aspergillus versicolor Derived from Tobacco

Chemistry of Natural Compounds - Two new (1 and 2) and four known (3–6) CPA-type indole alkaloids were isolated from the fungus Aspergillus versicolor. Their structures were determined by...     

Design and simulation of a wire scanner for the CSNS linac

In this paper,we report the design and simulation of a wire scanner for the linac of the CSNS(China Spallation Neutron Source).The wire scanner is used to measure the transverse beam profile andthe emittance.The effect of beam energy change upon the mechanical design of the wire scanner must beconsidered.The simulation results of heat on the two specified wires,tungsten and carbon,by using the finite element method software,ANSYS,are presented.In addition,the effect of wire deformation on the beam profile measurement is qualitatively analyzed,and the signal level of the wire scanner is discussed.     

Design of the low energy beam transport line for the China spallation neutron source

The design of the China Spallation Neutron Source (CSNS) low-energy beam transport (LEBT) line, which locates between the ion source and the radio-frequency quadrupole (RFQ), has been completed with the TRACE3D code. The design aims at perfect matching, primary chopping, a small emittance growth and sufficient space for beam diagnostics. The line consists of three solenoids, three vacuum chambers, two steering magnets and a pre-chopper. The total length of LEBT is about 1.74m. This LEBT is designed to transfer 20mA of H-pulsed beam from the ion source to the RFQ. An induction cavity is adopted as the pre-chopper. The electrostatic octupole steerer is discussed as a candidate. A four-quadrant aperture for beam scraping and beam position monitoring is designed.     

SrB_6的固相合成及其形成机理

稀土、碱土金属硼化物属难熔类金属无氧型化合物具有高熔点、高强度和化学稳定性高的特点其中许多还具有特殊的功能性如低的电子功函数、比电阻恒定、在一定温度范围内热膨胀值为零、不同类型的磁序以及高的中子吸收系数等１～４。这些优越性能决定其在现代技术各种器件组元中有广泛的应用前景。许多国家相继开展了该类材料的研究其中ＳｒＢ６及其复合材料用作高温绝缘体、核反应堆的控制棒等已引起多方重视此外文献５用扫描隧道电子显微镜分析了ＳｒＢ６的结构与性能在研究铝合金的变质过程中发现ＳｒＢ６能显著缩短有效变质时间６。但迄今…     

The Performance Improvement and Its Application of Beijing Proton Linac

The main characteristics,performance improvement,status,and its application of Beijing Proton Linac are described in this paper.     

Design of magnet and control of the beam emittance for Penning H^- ion source

The design requirement and principle of the deflection magnet for Magnetron and Penning H- ion source are discussed. It is proved that there exists a maximum emittance for the beam that may be transformed by the magnet into a state with equal Twiss parameters of αr =αy and βr =βy, which is the requisite condition to get a minimum emittance at the entrance of RFQ after transporting by a LEBT with solenoids. For this maximum emittance, the corresponding magnetic field gradient index is 1.